In the manufacture of magnetic heads for storage devices, atomic force microscopy (AFM) is commonly used for pole-tip recession (PTR) measurements due to its ability to resolve sub-nanometer changes in topography. However, magnetic head scan sizes must generally be relatively large to encompass the reader and writer shields as well as the air bearing surface (ABS). The ABS is assumed to be flat on average and is used to identify and remove undesirable artificial trends (e.g., artifacts) in the lateral (e.g., x and y) and vertical (e.g., z) directions of AFM scans in a process referred to as leveling. The ABS is also chosen as the reference position against which important characteristics such as the step heights in the shield/pole region are measured. Due to its importance, approximately fifty percent of the scan is often dedicated to the ABS alone. However, features such as the writer pole and reader can be two to three orders of magnitude smaller than the PTR scan size. The scan resolution necessary to adequately measure these areas along with PTR areas therefore involves a prohibitively low throughput. Smaller separate high-resolution scans can be run on these features, but the ABS generally cannot be included, thus making leveling/referencing challenging.
To address these sorts of referencing challenges, Park Systems offers a commercial method to integrate high and low resolution AFM scans by way of a programmable data density (PDD) option that is implemented during the measurement with its metrology tools. However, this method results in higher costs for the metrology tools and in additional artifacts to both PTR and writer pole recession (VPR) scans which are highly undesirable. As such, a method for referencing related magnetic head scans to address these deficiencies by reducing processing requirements for high resolution imaging is needed.